Running these tests with e.g. Fomapan 400 and their new Retropan 320 soft I came to the conclusion that e.g. in HC-110 (B=1+31) (also a popular developer) Fomapan 400 reached iso 200 and their Retropan 320 indeed (almost) iso 320.
So not so strange that people don't like FP400 in push to iso 800 because the reality is an iso 200 film pushed to iso 800 which means +2F stops, severe loss details in the shadows and hardly usable negative for the enlarger prints.
In fact: FP200 is better to push to iso 800 then the FP400 film. About their Retropan 320 I did some tests on iso 640 with still a lower Gamma but that has to do this film is especially made for low contrast, hence the "Soft" name of this Fomapan film.
